fix: retry sysSelect in Darwin on EINTR

In certain situations, the read of the terminal fd will fail, returning
an EINTR on Darwin. This causes the status report to be printed to
stdout, since the read never occurs.

Similar to issue golang/go#22838

Fixes: #12

Author: justenwalker

termenv_unix.go

@@ -4,6 +4,7 @@ package termenv
 
 import (
 	"os"
+	"runtime"
 	"strconv"
 	"strings"
 	"syscall"
@@ -75,15 +76,23 @@ func readWithTimeout(f *os.File) (string, bool) {
 	fd := f.Fd()
 	readfds.Bits[fd/64] |= 1 << (fd % 64)
 
-	// Use select to attempt to read from os.Stdout for 100 ms
-	err := sysSelect(int(fd)+1,
-		&readfds,
-		&syscall.Timeval{Usec: 100000})
-
-	if err != nil {
+	for {
+		// Use select to attempt to read from os.Stdout for 100 ms
+		err := sysSelect(int(fd)+1,
+			&readfds,
+			&syscall.Timeval{Usec: 100000})
+		if err == nil {
+			break
+		}
+		// On MacOS we can see EINTR here if the user
+		// pressed ^Z. Similar to issue https://github.com/golang/go/issues/22838
+		if runtime.GOOS == "darwin" && err == syscall.EINTR {
+			continue
+		}
 		// log.Printf("select(read error): %v", err)
 		return "", false
 	}
+
 	if readfds.Bits[fd/64]&(1<<(fd%64)) == 0 {
 		// log.Print("select(read timeout)")
 		return "", false